Assessment of the impact of animal waste quality on its energy recovery based on direct lipid combustion and the biodiesel pathway for distributed generation

The slaughterhouse industry generates a considerable volume of by-products, which are widely distributed and classified as carbon neutral. The integration of these by-products into waste-to-energy technologies presents a challenge due to their properties, which make energy recovery difficult. Their high moisture, protein, and lipid content limits their integration into technologies such as pyrolysis or anaerobic digestion. The integration of animal lipids into the biodiesel pathway is a well-established approach, but it also presents challenges due to its properties, which limit their integration compared to other feedstocks. This manuscript presents an in-depth study of the integration of animal by-products generated in industry, classified according to their biofuel generation capacity. The study is focused on the direct lipid combustion and the biodiesel pathway for distributed electricity generation at the European level. The integration of simulation models provides valuable insights into the dynamic behavior of systems based on processing step, supporting informed decision-making for future research on these technologies. The Net Energy Ratio, as an energy indicator, shows that depends mainly on by-product quality and the type of technology, taking values between 0.2 and 6. In addition, 63 % of by-products are energy viable through direct combustion, compared to 20 % for the biodiesel pathway. Furthermore, this study suggests that the energy viability of both pathways tends to coincide for low-fat by-products, encouraging approaches based on by-product classification. The results show that these byproducts could generate up to 59.6 MWh/year, contributing up to 6.6 % of the energy distributed in Europe in an improved scenario. • Assessmet of the dynamic behavior of energy recovery from animal waste. • Study of the integration of animal waste for energy recovery based on waste quality. • Integration of animal waste into direct lipid combustion and biodiesel pathways. • Energy recovery from animal waste in Europe based on distributed generation.